As technology evolves into era of sub-micron (e.g., 65 nm and beyond), there is a desire to integrate memory array, high voltage (HV) devices and high speed logic circuit elements into a single chip or integrated circuit (IC) to form an embedded memory. Nevertheless, it is difficult to integrate these different types of devices in a single chip since each of these devices has different requirements. For example, it is necessary to alter or change the logic processing steps to accommodate for the memory cell and the high voltage devices. This undesirably complicates the manufacturing process and increases the manufacturing cost. Moreover, the reliabilities of the memory and high voltage devices may degrade during integration.
From the foregoing discussion, it is desirable to provide a reliable, high performing and simplified solution for integrating different types of devices in the same IC.